AQUEOUSSOLUBILITIES OF ALPHATIC KETONES
Aug., 1940
7. The rotation of the ethyl groups of n-butane is hindered by a potential of the order of 30,000 cal./mole. 8. It is shown that reliable thermodynamic
[CONTRIBUTION FROM
THE
1923
functions for n-butane at high temperatures may be obtained despite uncertainty in the vibrational frequency assignment. STATE COLLEGE, PENNA.
RECEIVED MARCH18, 1940
DEPARTMENT OF CHEMISTRY, GREENSBORO COLLEGE ]
Aqueous Solubilities of Some Aliphatic Ketones BY P. M. GINNINGS, DOROTHY PLONKAND ELOISECARTER In view of the dearth of information in the literature as to the solubility in water of aliphatic ketones and the relationships already found between the molecular structure and solubility of aliphatic alcohols, the aqueous solubilities of twelve such ketones have now been measured. The solubilities (Table I) were determined by the same volumetric method as was used for the alcohols, and are considered accurate to within 0.05 weight per cent. except that 0.20 weight per cent. should probably be allowed in nos. 1 and 2. The ketones were of the best Eastman Kodak Co. grade except nos. 5, 8, 9 and 10, which were prepared from the corresponding secondary alcohols by the method of Yohe.2 All were purified by fractional distillation through a 1-meter column, usually from barium oxide. Nos. 1, 3, 6, 8 and 12 were further purified by means of sodium bisulfite.
4-Methylpentanone-2 20 2.04 97.59 25 1 . 9 1 97.93 30 1.78 97.80
,9951 ,9944 ,9932
,8092 ,8018 ,7981
7
0.8012 106.0-106.1
3.3-Dimethylbutanone-2 20 2.04 98.35 25 1 . 9 0 98.24 30 1.77 98.14
,9954 .9946 .9933
.5097 ,8053 ,8010
8
0.8072 127.5-127.6
Hexanone-2 1.75 97.88 1.64 97.75 1.53 97.64
,9959 .9950 .9938
.8154 ,8117 ,8079
9
0.8059 115.0-115.1
4-Methylpentanone-3 20 1.63 98.79 25 1.52 98.69 30 1.42 98.60
,9959 ,9952 ,9941
.8128 .8088 ,8047
10
0.8111 123.6-123.7
Hexanone-3 1.57 98.47 1.47 98.38 1.38 98.30
,9962 ,9952 ,9943
,8176 ,8134 ,8087
11
0.7900 125.4-125.5
,9976 .9966 .9953
,8044 ,8003 .7962
12
0.8115 151.2-151.3
,9978 .9967 .9Y53
,8177 ,8141 ,8098
20 25 30
20 25 30
2,4-Dimethylpentanone-3 20 0.59 99.24 25 .57 99.19 30 .56 99.15
TABLE I of pure dz04, $11, 8'34 ketoneoand of the liquid phases h. p. C. Temp., Water Ketone Wt. % (760 mm.) 'C. ketone rich rich Butanone-2 0.8007 20 27.33 88.41 0.9620 0.8353 80.7-80.8 25 .9611 ,8322 25.57 88.28 30 24.07 88.15 .9615 ,8270
d254
0.8189 93.1-94.0
0.8018 102.2-102.3
3-Methylbutanone-2 20 6.53 97.61 25 6.08 97.43 30 5.68 97.24
.9908 .9901 ,9890
,8328 ,8284 ,8238
Pentanone-2 5.95 96.70 5.51 96.52 5.18 96.32
.9903 .9897 ,9887
,8147 .8103 ,8059
20 25 30
0.8116 101.8-101.9
Pentanone-3 20 5 . 0 8 98.55 25 4.81 98.38 30 4.50 98.17
.9925 ,9915 .9901
.8195 .8150 ,8108
0.8083 117.4-117.5
3-Methylpentanone-2 20 2.26 08.05 25 2.09 97.97 30 1.93 97.83
.9926 ,9944 ,9935
,8328 ,8131 ,8088
(1) For instance, unsaturated alcohols, Ginnings, Herring and Coltrane, THIS JOURXAL, 61, 807 (1939). (2) Yohe, Lauder and Smith, J . Chem. Education, io, 374 (1933).
.
0.7969 115.6-115.7
20 25 30
Heptanone-2 0.44 98.69 .43 98.59 .40 98.48
Park and Hofman, I d . Eng. Chem., 24, 134 (1932), give data for Nos. 1, 3, 8 and 12 a t room temperatures (about 25"). Evans, Ind. Eng. Chem. Anal. Ed., 8 , 208 (1936), has measured no. 1 a t 20" using a volumetric Gross, Saylor and Gormethod obtaining 26.7 wt. %. man, THISJOURNAL, 55, 650 (1933), have measured no. 4 accurately a t 30°, obtaining 4.48wt. %.
Discussion The most important factor is of course the molecular size (nos. l, 3, 8 and 12) as the smallest ketone is the most soluble (acetone is soluble in water in all proportions). In a group of isomeric ketones, solubility tends to increase as molecular structure becomes more comDact (nos. 3 and 2 : 10 and 9; 8, 6, 5 and 7). Most unexpected was the effectof the position of the carbonyl group. In alcohols increasing solubility follows move-
1924
HARRYB. WEISERAND W.0, MILLIGAN
ment of the hydroxyl group toward the center of the molecule but in these ketones, the carbonyl group tends to decrease the solubility as it is moved toward the center (nos. 3 and 4; 6 and 9; 8 and 10). The effect of the carbonyl position is especially noticeable in the case of no. 7, resulting in an unexpected decrease in the solubility (nos. 8, 6, 5 and 7). These ketones all become less soluble with increasing temperature.
[CONTRIBUTION FROM THE
Vol. 62
Summary Aqueous solubilities of twelve aliphatic ketones have been determined for 20, 25 and 30’. Low molecular weights and low temperatures result in large solubilities. The most compact isomers tend to be most soluble but movement of the carbonyl group toward the center of the molecule tends to reduce the aqueous solubility. GREENSBORO, N. C.
DEPARTMENT OF CHEMISTRY,
THE
RECEIVED MAY10, 1940
RICEINSTITUTE ]
The Electrolyte Coagulation Process: the Influence of Dilution of Sol on the Adsorption of Precipitating Ions BY HARRYB. WEISER AND W. 0. MILLIGAN The concentration of electrolytes required to coagulate hydrophobic sols varies with the concentration of sol, a phenomenon first observed by Mukopadhyaya. Burton and Bishop2 formulated the rule that, in general, the precipitation value of univalent precipitating ions increases with dilution of sol; that of bivalent ions is almost constant and independent of the sol concentration; and that of trivalent ions decreases with the sol concentration. Weiser and Nicholas3 pointed out that Burton and Bishop’s rule is not generally applicable since with many sols, especially those of the hydrous oxides, the precipitation value of electrolytes decreases with dilution of sol irrespective of the valence of the precipitating ion. Sorum4 showed, however, that certain hydrous oxide sols which do not follow Burton and Bishop’s rule when relatively impure will obey the rule after sufficient purification by dialysis, but no explanation is offered for this behavior. Because of the limitations of rules of electrolyte coagulation which attempt to formulate the conditions for reducing the potential on the dispersed particles to a critical value, Ostwald5 introduced the principle that the ‘dispersion medium rather than the colloidal particles should be in a corresponding (in the simplest case identical) physicalchemical state for coagulation to take place. It is argued that coagulation should take place a t the (1) Mukopadhyaya, THISJOURNAL, 37, 2024 (1915); Kruyt and van der Spek, Kolloid. Z.,26,3 (1919). (2) Burton and Bishop, J . Phys. Chem., 24, 701 (1920); Burton and MacInnes, ibrd., 26, 517 (1921). (3) Weiser and Nicholas, ibid., 26, 742 (1921). (4) Judd and Sorum, THIS JOURNAL, 62, 2598 (1930); Fisher and Sorum, J . Phys. Chem., 39, 283 (1935); 44, 62 (1940). (5) For a survey with references see .ibrd,42,981 (1938).
same activity coefficient of the precipitating ion (f+ for negative sols andf- for positive sols) irrespective of the salt employed. The activity coefficient of a single cation, for example, is given in accord with the Debye-Hiickel theory by a relation of the form -log f+ = 0.5 ( z + ) ~2/m, in which z is the valence of the cation, n+ the number of cations in the molecule and u is the ionic strength which is given by the expression u = 0.5 [ m + ( ~ +-) ~m - ( ~ - ) ~where ], m+ and mare the molarities of the cation and anion, and z+ and z- are the valences of the respective ions in the coagulating electrolyte. Ostwald’s simple formulation, f + (or f-) = constant, is necessarily limited in its applicability.6 In the first place, the precipitation values of electrolytes vary in different ways with dilution of sol so that in general the activity coefficient of the precipitating ion a t the coagulation value cannot be constant over any wide range of concentration. In the second place, if Ostwald is right that the dispersion medium should be in the same physicalchemical state for coagulation to take place, then the activity coefficients of the precipitating ions in equilibrium with the particles should be compared rather than the activity coefficients calculated on the basis of the total amount added to effect coaguiation. If such a comparison is made there is no reason to believe that the critical activity COefficients will approach a constant value for ions of varying valence since only a small percentage of univalent ions is adsorbed a t their precipitation value whereas a large percentage of most multi(6) Cf. Weiser, “Inorganic Colloid Chemistry,” Vol. 111, John Wiley and Sons, New York, N.Y., 1938,pp. 190 et seq.
